matplotlib/basemap

Using mercator projection: I want to color only lands/countries, and all land(except Antarctica) plus all ocean gets colored

Code-Sage opened this issue · 2 comments

Code-Sage commented

This code is from Basemap docs pages, with some changing to focus on my issue at hand.
I want to color(in this case, magenta) all lands(Antarctica can be overlooked), and all ocean should be white like Antarctica is right now. The shapefile is from here

from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
from matplotlib.patches import Polygon
from matplotlib.collections import PatchCollection
from matplotlib.patches import PathPatch
import numpy as np

fig = plt.figure(figsize=(20,20))
ax = fig.add_subplot(111)

map = Basemap(llcrnrlon=-180,llcrnrlat=-85,urcrnrlon=180.,urcrnrlat=85, projection='merc')

map.readshapefile('countries_lakes/ne_10m_admin_0_countries_lakes', 'units')

patches = []

for info, shape in zip(map.units_info, map.units):
    patches.append(Polygon(np.array(shape), True))
        
ax.add_collection(PatchCollection(patches, facecolor= 'm', edgecolor='k', linewidths=1.))

plt.savefig('dem.png', bbox_inches='tight')

dem

molinav commented

Hi, @Code-Sage! Sorry for being so late replying. I cannot reproduce your problem, what Python version and basemap version are you using? Can you try out the following code snippet?

import sys
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.collections import PatchCollection
from matplotlib.patches import Polygon
from mpl_toolkits.basemap import __version__ as basemap_version
from mpl_toolkits.basemap import Basemap

print("Python version: ", sys.version)
print("Basemap version:", basemap_version)

fig = plt.figure(figsize=(20, 20))
ax = fig.add_subplot(111)

bmap = Basemap(projection="merc",
               llcrnrlon=-180, llcrnrlat=-85,
               urcrnrlon=+180, urcrnrlat=+85)

bmap.readshapefile("countries_lakes/ne_10m_admin_0_countries_lakes", "units")

patches = []
patches_kwds = dict(facecolor="m", edgecolor="k", linewidths=1.)
for info, verts_i in zip(bmap.units_info, bmap.units):
    patches.append(Polygon(np.array(verts_i), closed=True))

ax.add_collection(PatchCollection(patches, **patches_kwds))

plt.savefig("dem.png", bbox_inches="tight")

It returns the following in my console:

Python version:  3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)]
Basemap version: 1.3.8

And it saves the following image (probably what you were expecting):
dem